NullReferenceException at Save_FilesError

Everytime I Ban Someone They Can Just Join Back Errors

Failed to call hook 'OnServerSave' on plugin 'EnhancedBanSystem v5.2.4' (NullReferenceException: Object reference not set to an instance of an object)
  at Oxide.Plugins.EnhancedBanSystem.Save_Files () [0x00000] in <2ea2ce62a70d4c1a89c99b838868df62>:0
  at Oxide.Plugins.EnhancedBanSystem.OnServerSave () [0x00030] in <2ea2ce62a70d4c1a89c99b838868df62>:0
  at Oxide.Plugins.EnhancedBanSystem.DirectCallHook (System.String name, System.Object& ret, System.Object[] args) [0x01408] in <2ea2ce62a70d4c1a89c99b838868df62>:0
  at Oxide.Plugins.CSharpPlugin.InvokeMethod (Oxide.Core.Plugins.HookMethod method, System.Object[] args) [0x00079] in <60c318df79ed41688ea59335e48d61ad>:0
  at Oxide.Core.Plugins.CSPlugin.OnCallHook (System.String name, System.Object[] args) [0x000d8] in :0
  at Oxide.Core.Plugins.Plugin.CallHook (System.String hook, System.Object[] args) [0x00060] in :0

Corrupt data file most likely